In Vitro Antioxidant Activity of Peptides from Simulated Gastro-Intestinal Digestion Products of Cyprinus carpio haematopterus Scale Gelatin

A two-stage simulated gastro-intestinal (GI) digestion model (2 h pepsin treatment and subsequent 2 h pancreatin treatment at 37 °C) was used to explore the antioxidant activity of the digested products of Cyprinus carpio haematopterus scale gelatin with different molecular weights (MW). From the gastric phase to the intestinal phase, the hydrolysis degree of the products increased from 2.6 ± 0.4% to 16.9 ± 0.7%. The fraction of 0–1 kDa (JCP3) exhibited the best antioxidant activities in hydroxyl radical scavenging, reducing power, and metal chelating activity. The fraction of 1–3 kDa (JCP2) exhibited the best 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. However, the fractions of 0–1 kDa (JCP3) and 1–3 kDa (JCP2) showed similar inhibitory activity of lipid peroxidation. The results indicated that Cyprinus carpio haematopterus scale gelatin can be digested in the gastrointestinal tract. Furthermore, the digested products had antioxidant activity.